Frame spacer

ABSTRACT

A box-spring type construction formed of an upper frame, a lower frame and interconnecting coil springs, which may be utilized in automobile seats and the like, and having a horizontally elongated netting secured to both the upper and lower frames at the front of the construction. The netting extends vertically between the frames to limit expansion of the springs. The netting is formed of a plurality of thin vertical strands which are joined by a plurality of thin horizontal strands with all the strands being in a first plane. Each strand is formed of a slippery, flexible material having limited resiliency which has been uniaxially stretch oriented in its longitudinal direction to increase tensile strength. The strands form a netting or lattice and the joints of the strands distribute any uneven tensile forces, resulting in an increased tension absorption.

United States Patent 1 l v 3,823,429 r Ambrose [5 1 FRAME SPACER [75] Y Inventor: Jere B. Ambrose, Pontiac, Mich.

[73] Assignee: Northern Fibre Products Company, Birmingham, Mich. r 221 Filed: ,Mar. -,23',"1 973.

111 Appl. No.: 344,246

4 52, use: ..s/34s R,5/354, 5/360, 1 297/452, 297/1210. 2 51 .1m.c1 A47c 7/22, A470 7/14 [58] Field of Search ..5/345,354,360, 191;

297/452, DIG. 1, DIG. 2

[4511 July- 16, 1974 Primary Examiner-CasmirA. Nunberg Attorney, Agent, or,Firm-Cullen, Sett le, Sloman 8: Cantor [571/ i :ABSTRACT A box-spring typelconst-ruction formedof an ripper frame, a lower frame and interconnecting coil springs,

, which may beatiliaed inaut'omobile seats and the like, I and having a hori zontallyelongated netting secured to both the upper and lowerf rames at the front of the construction. The netting extends vertically between the frames to limit expansionof ,the springs. The netting is formed of a pluralityof thin vertical strands which are joined by a plurality of thin horizontal strands with all the strands being :in a first plane. Each [56] References Cited strand is formed of a slippery, flexible material having UNITED S A PATENTS limited resiliency which has been uniaxially' stretch 2,296,559 9/1942 Krakauer 5/360 oriented in its longitudinal direction to increase tensile 3,273,862 9/1966 Miller 256/73 strength. The strands form a netting orlattice and the 3,3i5,283 Larsen 4 joints of the trands distribute any uneven tensile i forces, resulting in an increased tension absorption.

2 Claims, 7 Drawing Figures Pk i I l I I2 Mail FRAME SPACER Frames for seats in automobiles and the like, as well as for other applications, generally consist of a boxspring construction having an upper wire frame spaced above a lower wire frame with the two frames interconnected by vertically positioned coil springs. Seat padding is placed upon the upper frame and thereafter the final upholstery is applied upon the upper surface of the padding and may also be wrapped around the edges of the frame construction.

The coil springs are under slight compression in a rest position with the seat unoccupied. When a user sits on a seat or when a load is applied to a seat, the springs are compressed and the upper wire frame, with its padding and upholstery cover, moves downwardly toward the lower frame. Upon release of the weight against the seat, the stored energy in the spring is converted to kinetic energy causing the springs to expand. Because the release of weight from the seat is relatively sudden and uneven, the springs tend to overexpand and thus apply an irregularly distributedtension force to the upholstery fabric which is stretched around the edge of the frame.

As may be appreciated, the upholstery fabric repeatedly buckles when the seat is occupied and is repeatedly placed in tension as the seat becomes unoccupied. This causes the upholstery to pucker, tend to crack if it is a plastic-like or vinyl-like material, and tend to tear or rip. if it is a fabric or leather material.

Various types of limiting restraining means have been applied to seat constructions to reduce the tension load upon the upholstery fabric and to limit the expansion of the springs. One such limiting means has been a burlap spacer arranged around the front of the constructionbetween the upper and lower frames and secured thereto. The burlap buckles when the seat is compressed and, the burlap straightens to absorb tension forces when the seat becomes unoccupied and the springs expand.

However, none of the prior art limiting means compensates for the irregular or uneven tension forces createdby uneven removal of weight from the seat.

Thus, the invention herein is directed to an improved spacer for the edge of a box-spring type construction which eliminates the disadvantages of prior devices and which more effectively absorbs and distributes the uneven tension forces of the expanding coil springs, thus better protecting the upholstery fabric.

SUMMARY OF THE INVENTION The invention herein relates to a seat edge spacer of the form utilized to secure the edges of an upper seat frame and a lower seat frame together. The spacer is formed of a plurality of vertical strands of a flexible, limited resiliency material joined by a plurality of hori zontal strands of flexible limited resiliency material to form a lattice or netting. All of the strands are in a first plane with the joints between the strands lying partially in said plane and extending slightly above the plane. Each of the strands is uniaxially stretch oriented to increase tensile strength so that the overall lattice or netting is stretch oriented in both thevertical and horizontal direction. The vertical strands may be turned over into a hem through which a supporting wire may be extended for stiffening and reinforcing the upper and lower edges of the lattice. The joints between the vertical strands and the horizontal strands serve to distribute uneven stress among the various strands of the netting.

These and other objects and advantages of the present invention will become more apparent upon reading the following detailed description of which the attached drawings form a part.

' BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, wherein like reference numerals identify corresponding parts:

FIG. 1 is a fragmentary end view, partly in cross section, of a seat construction including the spacer of the present invention;

FIG. 2 is a view of the seat of FIG. 1 taken in the direction of arrows 22;

FIG. 3 is a perspective illustration of a portion of the lattice spacer of the present invention;

FIG. 4 is an enlarged illustration of an individual joint between the vertical and horizontal strands of the lattice;

FIG. 5 is another perspective illustration showing the opposite side of the lattice spacer;

FIG. 6 is an enlarged end view of a single joint in the lattice spacer of the present invention; and

FIG. 7 is a fragmentary perspective illustration of the lattice spacer joined to one frame member.

DETAILED DESCRIPTION FIGS. 1 and 2 illustrate the conventional box coilspring type seat construction which is generally formed of an upper wire frame 10 spaced above and aligned with a lower wire frame 12. Each of the frames has flat,

springy metal cross struts l4 and 16 to which are connected the upper and lower surfaces of vertically posi- I tioned coil springs 18.

The wire frames 10 and 12 are generally arranged in horizontal planes with the lower frame secured to the floor of an automobile and with the upper frame at a slight angle with respect to the lower frame to follow the general angle at which persons are most comfortable when sitting in an automobile.

The upper wire frame 10 is typically covered with a cushion or pad-like material 20 which has a certain degree of resiliency and an upholstery fabric 22 is secured on top of the cushion. The fabric 22 is secured over the cushion 20 and over the front, sides and rear of the frame construction and secured to the bottom of the lower frame in a conventional manner.

When the seat is occupied by either a user or by the storage of some weight, the springs 18 are compressed and the upper wire frame and its struts bend resiliently so that the seat conforms to the contour of the person or object thereon. This causes a bending, buckling or puckering of the fabric 22. In order to avoid a rebound of the springs when the user sits on them, the springs are normally held, at rest, under slight compression. Therefore, when the user releases the weight from the seat, the springs 18 tend to overexpand thus tending to move the upper and lower wire frames 10, 12 further apart than their nonnal rest position. This puts anincreased tension on the fabric 22. The repeated buckling of the fabric when the seat is occupied, together with the repeatedtension on the fabric as the weight is removed from the seat, tends to cause the fabric to both wear and rip. In addition, if the fabric is vinyl,

plastic or the like the repeated buckling and tension tends to cause the vinyl to crack.

Furthermore, since the upper frame follows the general contour of the body, the release of weight from the seat tends to be uneven. This creates uneven tension upon different portions of the fabric 22.

Means are provided to maintain the spacing of the seat at rest without tension on the fabric 22 and to reduce or eliminate the tension on the fabric when the seat becomes unoccupied. The means operates to absorb the tension of the coil springs.

Specifically, a spacer 24 is secured between the upper frame 10 and the lower frame 12. The spacer is in the form of an open netting or lattice and comprises a plurality of vertical strands 26 which are joined by a plurality of horizontal strands 28 as at a joint 30.

To provide a better operation and life of the spacer, there are certain characteristics which are necessary. First, the spacer must be flexible enough so that it may buckle with the fabric when a load is placed on the seat. Second, the strands must have a certain degree of longitudinal resiliency so that there is no tensile fracture of the strands when the load is removed from the seat. However, this longitudinal resiliency must be limited to avoid stretching of the strands.

Another characteristic of the strands is that they be operated within their elastic limit to avoid fatigue. Additionally, since the temperature inside a closed automobile may reach low limits in cold weather and may reach quite hot limits if the automobile is left parked in the sun, the strands must maintain their desired characteristics within a temperature range of approximately -50F to approximately +200F. Also, the strands must be smooth and slippery to avoid catching or snagging the fabric 22.

A critical feature is that the material be able to distribute any uneven tension in the strands such as occasioned by uneven unloading of the seat.

A preferred material to be used as the strands of the netting is polypropylene. However, other polymerized resinous plastics and fluoridated hydrocarbons may also be satisfactory.

The spacer 24 is formed as an open netting or lattice having spaces 32 between adjacent strands. These spaces are substantially wider than the thickness of an individual strand 26 or 28. The benefit of this open space construction is that it permits a free flow of air to thereby permit the fabric 22 to breathe.

The netting, which may be extruded, has all of its vertical and horizontal strands in a first plane. Each joint 30 is integrally formed between a horizontal strand and a vertical strand. Viewed from the front of the netting each joint includes four arcuate portions 34 connecting the strands together. Viewed from the rear of the netting, each joint lies substantially in the plane of the strands with the joint having a protrusion or bump 36 extending slightly above the first plane.

Each strand is uniaxially stretch oriented in its longitudinal direction to increase the tensile strength of the strand. When the strands are placed together in a lattice or net spacer, the finished spacer has the property of being biaxially stretch oriented in both the vertical and horizontal directions.

One importance of the integral joints 30 is that they transmit stress from one strand to another strand. Therefore, uponthe uneven removal of a load from the seat, the uneven rebound of the springs 18 and the uneven frame motion tends to be reduced and limited by this distribution of tensile stress through the joints 30 to the several strands.

There are various ways to secure the spacer 24 between the upper frame 10 and the lower frame 12. A preferred way is illustrated in FIG. 7 and includes looping a longitudinal edge of the spacer about itself and inserting a stiffening rod 38 of metal or the like through the loop. The loop may be secured by stitching or the like so as to form a hem and the spacer secured to the frame by hog rings 40 as is conventional.

Because of the biaxial strength orientation and the distribution of forces by the joints, the lattice spacer is substantially nonstretchable in its planar direction and it absorbs tension equally in all directions. Thus, it protects against tension, vertical as 'well as angular, from being transferred to the fabric at the edges of the seat. The strands are not affected by moisture or heat within the desired operating range. v

The foregoing is a description of one embodiment of the present invention and should not be read in a limiting sense but only as describing the underlying concept. The invention may be further developed within the scope of the following claims.

What is claimed is:

1. In a box-spring type seat construction formed of a pair of roughly flat and horizontally arranged springy wire-like frames, one located above the other in vertical alignment therewith, and with generally vertically arranged coil springs secured between and interconnecting the two frames for resilient movement of the frames towards and away from each other, and with a cushioning pad arranged upon the upper frame, and upholstery material covering the pad and the side edges of the seat construction and spanning the spaces between the edges of the two frames, to define a seat having a front and side edges and an upper seating surface, the improvement comprising:

a horizontally elongated, narrow netting extending the length of at least the forward seat edge and arranged in a vertical plane between the upper and lower frame forward edges, closely adjacent to and behind the upholstery fabric covering the forward edge of the seat;

said netting being formed of a plurality of thin vertical strands, said vertical strands being joined by a plurality of horizontal strands, said vertical and horizontal strands all being in a first plane and having spaces therebetween which are of substantially greater width than the thickness of the strands to form an open lattice-type netting;

each of said strands being formed of a slippery, flexible, limited resiliency material which has been uniaxially stretch oriented in its longitudinal direction to increase tensile strength and to form a netting which is biaxially oriented;

said netting having a stiff, wire secured to its upper and lower long edges and extending the length thereof, and mechanical fastening means, connecting each of said wires to its adjacent frame edge portion so that the netting vertically spans the space between the forward edges of the frames;

the, netting being of a width, in its vertical direction, corresponding to the desired spacing between the frames, when the seat is unweighted, so that the vertical strands are under slight tension, and wherein application of a weight to the seat surface causes compression of the coil springs and the forces;

upper frame member to mo downwardly ow rd and said netting having one relatively smooth and the lower frame member, thus causing the netting Slippery Surface f reducing f i ti l d b and its adjacent upholstery fabric to buckle; tween the strip and the adjacent upholstery surand wherein release of the weight causes the springs 5 face to expand and the upper frame to separate from the lower frame, with the netting H mm H g the expan 2. The construction of claim 1 wherein the oints be Sion Ofthe springs and Separation of the frames and tween the vertical strands and the horizontal strands the netting absorbing the tension forces caused by are Integral protrusmns, h protruslon g expansion of the springs and the joints distributing 10 above said first plane and positioned toward said coll uneven tension forces to surrounding strands to p ng protect the upholstery fabric from such tension 

1. In a box-spring type seat construction formed of a pair of roughly flat and horizontally arranged springy wire-like frames, one located above the other in vertical alignment therewith, and with generally vertically arranged coil springs secured between and interconnecting the two frames for resilient movement of the frames towards and away from each other, and with a cushioning pad arranged upon the upper frame, and upholstery material covering the pad and the side edges of the seat construction and spanning the spaces between the edges of the two frames, to define a seat having a front and side edges and an upper seating surface, the improvement comprising: a horizontally elongated, narrow netting extending the length of at least the forward seat edge and arranged in a vertical plane between the upper and lower frame forward edges, closely adjacent to and behind the upholstery fabric covering the forward edge of the seat; said netting being formed of a plurality of thin vertical strands, said vertical strands being joined by a plurality of horizontal strands, said vertical and horizontal strands all being in a first plane and having spaces therebetween which are of substantially greater width than the thickness of the strands to form an open lattice-type netting; each of said strands being formed of a slippery, flexible, limited resiliency material which has been uniaxially stretch oriented in its longitudinal direction to increase tensile strength and to form a netting which is biaxially oriented; said netting having a stiff, wire secured to its upper and lower long edges and extending the length thereof, and mechanical fastening means, connecting each of said wires to its adjacent frame edge portion so that the netting vertically spans the space between the forward edges of the frames; the netting being of a width, in its vertical direction, corresponding to the desired spacing between the frames, when the seat is unweighted, so that the vertical strands are under slight tension, and wherein application of a weight to the seat surface causes compression of the coil springs and the upper frame member to move downwardly towards the lower frame member, thus causing the netting and its adjacent upholstery fabric to buckle; and wherein release of the weight causes the springs to expand and the upper frame to separate from the lower frame, with the netting limiting the expansion of the springs and separation of the frames and the netting absorbing the tension forces caused by expansion of the springs and the joints distributing uneven tension forces to surrounding strands to protect the upholstery fabric from such tension forces; and said netting having one relatively smooth and slippery surface for reducing frictional drag between the strip and the adjacent upholstery surface.
 2. The construction of claim 1 wherein the joints between the vertical strands and the horizontal strands are integral protrusions, each protrusion extending above said first plane and positioned toward said coil springs. 